import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
def main():
    x = int(readline())
    if x >= 30:
        print('Yes')
    else:
        print('No')
if __name__ == '__main__':
    main() import sys sys read = sys.stdin.buffer.read read sys.stdin.buffer.read sys.stdin.buffer sys.stdin sys stdin buffer read readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline readlines = sys.stdin.buffer.readlines readlines sys.stdin.buffer.readlines sys.stdin.buffer sys.stdin sys stdin buffer readlines def main():
    x = int(readline())
    if x >= 30:
        print('Yes')
    else:
        print('No') main x = int(readline()) x int(readline()) int readline() readline if x >= 30:
        print('Yes')
    else:
        print('No') x >= 30 x 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main read = sys.stdin.buffer.read sys.stdin.buffer.read read readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline def main():
    x = int(readline())
    if x >= 30:
        print('Yes')
    else:
        print('No') def main():
    x = int(readline())
    if x >= 30:
        print('Yes')
    else:
        print('No') main readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
def main():
    x = int(readline())
    if x >= 30:
        print('Yes')
    else:
        print('No')
if __name__ == '__main__':
    main()
